Statement of the Problem: In the past few decades there has been a dramatic increase in the number of new/improved alloys introduced to the dental profession for use in restorative dentistry. These alloys exhibit complex chemical compositions, and contain elements many of which have been of concern to researchers and others as to their biocompatibility in humans. Toxicity, and reactins of hypersensitivity have also been associated with some of these same components when used alone or when combined in an alloy system. The literature is lacking in definitive, scientific data that either supports or refutes these concerns, and few if any research reports can be found to assist the manufacturers of alloys or the profession in the efficacy of their long-term clinical usage. Approach to the Problem: It is apparent that a gathering together of internationally known researchers, educators, and clinicians from the dental and medical professions is needed with the intended purpose to assess the available knowledge about the composition and structure of alloys and their influence on biocompatibility, toxicity and hypersensitivity reactions in humans. A "Workshop" seems to be the best method with which to study this subject in that it will permit the bringing together of experts to interact in a comprehensive and organized manner. Each participant will act as a contributor and will be encouraged to present, discuss, question, or criticize the information presented. Conclusions will be based on factual scientific evidence and not on unsupported theories formulated from limited clinical observations. The Workshop will include approximately sixty contributors from throughout the world and involve five working days in seven simultaneous sessions to study, in some depth, the following: 1) clinical requirements, 2) laboratory requirements, 3) the role of the compositional elements, 4) corrosion of alloys, 5) biocompatibility, 6) toxicity, and 7) hypersensitivity. Objectives: The Workshop will serve to appraise the available knowledge concerning all aspects of the biocompatibility of cast and wrougth alloys used in treatment of oral disease; examine the evidence concerning the effects of such alloys on patients, dentists and technicians, and to relate these causes and effects. 2) Encourage the exchange of ideas and develop directions in reserch with regards to alloy systems. 3) Produce a publication to serve as a referenced source of the factual and scientifically supported research in this area, that will assist individuals as they pursue further knowledge through research about alloy systems and their potential use in dentistry.